Construction of the Tetranuclear Complex with Inter- and Intramolecular Stacking-Like Arrangement Composed of Planar Palladium(II) Units

Stereoselective Diels-Alder reaction between several (alpha),(beta)unsaturated ketones and acetoxy-l,3-butadienes is effectively performed by the promotion of diethylaluminum ethoxide under mild conditions. This reaction is successfully applied to the synthesis of optically active bicyclo[6.4.0]dodecanone 9 which corresponds to the BC ring system of 10-deoxy taxane derivatives from the 8-membered ring enone 7 and diene 2.